1. Field of the Invention
The present invention relates to a liquid crystal panel having compensation capacitors for balancing RC delay effect, and more particularly to a liquid crystal panel with uniform delay times in all control lines.
2. Description of the Related Art
Typically, a liquid crystal panel includes an active matrix substrate 10 having a plurality of data lines 13 and scanning lines 12, and the data lines 13 are perpendicular to the scanning lines 12, as shown in FIG. 1. A plurality of thin film transistors (TFTs) are formed in an active area B in which the data lines 13 and the scanning lines 12 cross each other at right angle.
The data lines 13 and the scanning lines 12 extend out of the active area B for transmitting signals from driving devices. A plurality of pads are formed in outer-lead bonding (OLB) areas 14 located on the periphery of the active area B, and are used for mounting the driving devices. Each of the OLB areas 14 is separately connected to one of fan-out areas 16 including a plurality of leads 15.
FIG. 2 shows an enlarged diagram of portion C in accordance with FIG. 1. The leads 15 run in straight lines and have equal thickness and width. The resistances of the leads 15 are different from each other because the lengths from the most outside lead 151 to middle lead 152 are apparently different, as shown in FIG. 3(a). The resistance of the lead 15 may be calculated as follows:       R    =          ρ      ⁢              L        S              ,where ρ, L and S respectively represent resistance, length, and cross sectional area of the lead 15.
The transverse axle in FIG. 3(a) represents the assigned numbers of the leads 15 from the leftmost one to the rightmost one with regard to FIG. 2. Furthermore, FIG. 3(b) shows a graph of the variable capacitances of all the leads 15. The product of resistance R and capacitance C is directly related to the delay time of a signal transmitted by either one of the data lines 13 or one of the scanning lines 12. Therefore, the delay time caused by RC delay effect is variable from the most outside lead 151 to the middle lead 152, as shown in FIG. 3(c).
Unfortunately, the variation of the delay time in the scanning lines 12 gives rise to a flicker phenomenon so as to deteriorate image quality. Therefore, the zigzag configuration of a fan-out area 16′ is provided for only reducing the variation of resistances, as shown in FIG. 4. Because all the leads is enclosed by the certain area of the fan-out area 16′, the total length of a zigzag middle lead 152′ is still shorter than the length of a straight outside lead 151′. In conclusion, the product R×C of the lead 151′ is different from that of the lead 152′. That is, the flicker phenomenon also exists in the liquid crystal panel with zigzag leads.